Lack Thereof or Lack Of? Which Is Correct? 

According to how you use the phrases ‘lack thereof’ and ‘lack of’, either of these options can be correct in certain circumstances. However, in contemporary usage, the word ‘lack of’ is more frequently used. This is due to the fact that the phrase “lack thereof” can come across as formal and stuffy. The use of the word ‘lack of’ is more casual and easier to understand by both native and non-native English speakers alike. 

For more information on these interchangeable phrases, including how they came to be and how they should be used within a sentence, continue reading below.

Definition of Lack Thereof and Lack Of

Both of the phrases, ‘lack thereof’ and ‘lack of’ have the same meaning. The phrase essentially means that there is not enough of whatever the phrase is mentioning. In a sentence order, it is most commonly used after the subject of the sentence.


His diploma, or lack thereof, cost a small fortune. 

In this instance, the speaker is pointing out the fact that ‘he’ does not have a diploma. The phrase is used to indicate that something is lacking.

Furthermore, you can use ‘lack of’ in the exact same way.

Taking the above example:

His diploma, or lack of one, cost a small fortune.

In the second example, the sentence comes off as more casual and easier going than in the first example.

Origin of the Phrases

The phrase ‘lack thereof’ came before the shortened ‘lack of’ in modern English. Part of the phrase ‘thereof’ dates back to ancient times, but the first recorded use of the word came in 1877. However, different spellings and forms of the word can be traced back to 1611 when King James first translated the Christian Bible.

Example Usage of ‘Lack Thereof’ and ‘Lack Of’

Because both of these phrases are interchangeable, using them both properly within a sentence is quite easy, as long as you remember that it usually comes after the sentence subject. Below are several examples of how to use either phrase in a sentence.

  • His wife never asked him how his job, or lack thereof, was going.
  • Her relevant work experience, or lack thereof, was never brought up during the interview process.
  • Now we have a bad hire because her work history, or lack of, was never mentioned in the interview process.
  • He never discussed his goals, or lack of, with anyone outside of his family.